Regenerative turbine fuel pumps typically draw fuel from a fuel tank, through a fuel inlet, and into a pumping chamber. As shown in FIG. 4, the pumping chamber is formed by a pump cover 20 and pump bottom 28 enclosing an impeller 16. Primary vortices are formed on either side of the impeller 16 in the pumping chambers 60 and 62 when fuel is pumped from a fuel tank to an automotive engine. If the inlet sides 72a and 72b of fuel inlet 70 are parallel, as in U.S. Pat. No. 4,723,888 (Watanabe et al.), crossing losses occur when fuel flowing along inlet side 72a toward primary vortices 82 in the pumping chamber 62 opposite inlet 70 interacts with primary vortices 80 in the pumping chamber 60 adjacent inlet 70. Pump efficiency is decreased by such losses and it is desirable to alter the fuel inlet to reduce such crossing losses.
Two such inlets are shown but not described in U.S. Pat. Nos. 4,538,958 (Takei et al.) and 4,556,363 (Watanabe et al.). Takei et al. employ an angled inlet 51 and Watanabe et. al. disclose an angled inlet 6. Neither of these discuss reduction of crossing losses nor disclose the advantageous inlet angles disclosed in the present invention. U.S. Pat. No. 5,141,396 (Schmidt et al.) discloses an angled inlet 8 which would increase, rather than decrease, crossing losses due to the steep lower side angle of the inlet 8. Schmidt et al also show a flat portion on the lower side of inlet 8 near the bottom of the impeller vane. U.S. Pat. No. 2,724,338 (Roth) discloses a turbine type pump having enlarged inlets (FIGS. 6, 8, 9, 12 and 15). German Patent 2,104,495 (Schwarz) employs an angled inlet 5 and an enlarged space 3 between the inlet 5 and the pumping chamber. The inlets for these patents do not, however, contribute to reduction of the crossing losses described above.